Attrition-mill



(No Model.) 1 '4 sheets-sheen 1f H. A. DUC, J1.

, ATTRITION MILL. No. 252,361. 1 Patented Jan. 17,1882.

(No Model.) 4 sheets-sheet 2.

H. A. DUC, Jr.

ATTRITIQN MILL. No. 252,36L Patented Ja,11.l7,1882."

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ATTRITION MILL.

No. 252,361. Patented Jan. 17,1882.

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(N0 Model.) 4 Sheets-Sheet 4.

H. A. DUO, Jr.

ATTRITION MILL.,

No. 252,361. Patented Jan. 17,1882.

N. PETERs PhumLnhegnphw. walhingmn, D. c.

1, UNriEn STATES PATENT trici-.

HENRY A. DUC, JR., OF CHARLESTON, SOUTH CAROLINA, ASSIGNOR OF ONE-HALF TO THOMAS F. ROWLAND, OF BROOKLYN, NEW YORK.

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SPECIFICATION forming part of Letters Patent No. 252,361, dated January 17, 1882-. 4 Applica-tion filed May 31, 1881. (No mdel.)

To all `whom it may concern and exact description, reference being had to the accompanying drawings.

In my improved mill the material is reduced by contact and friction against itself, as distinguished from a method of abrading or reducing the material against a grinding-surface not formedof the material itself'. My mill is also provided with means for taking up any wear which may occur in it.

'lhat which I consider new in my invention is claimed in the claims hereto annexed.

In my drawings similar letters ref'er to similar parts. l a

Figure l represents a general view in perspective, part of the apparatus being broken away, of my mill and separating-chambers; Fig. 2, a horizontal section through my mill, showing the feed-passages and plow; Fig. 3,

` a section through Fig. 2 on theline y y; Fig.A

4, a section through Fig. 2' on the line a; Fig. 5,`a view of the pipe-protecting shoe.

My mill is constructed as follows :4 l

A represents a revolving shell, tbe shape of which is shown clearly in Fig. '3. This shell is revolved upon a shaft, B, and the shell is preferably so attached to this shaft that when in operation-the mass of the material is situated in a plane which intersects the end of the shaft. By thismeans uniformity of' motion and reduction ofstrain are obtained. The shell A has a circular opening on the side opposite the supporting-shaft, as is clearly shown. Through this opening the feed, air-supply, and

air-exhaust passages pass, as also the plowb ar or wearing-surface.

A frame or casting, C, supporting the vari-` ous contrivances which operate in the mill, is provided, and may be supported in any suitable way. This frame carries a dovetailed slide, Y, (shownclearly in Fig. 2,) which can be slid u'p on the s'lideways and 4removed from the y mill. This slide contains passages for the airsupply, the supply of material to be ground, and the air-exhaust, and'it also supports the plow, hereinafter to be fully described. The

air returning from the separators enters the mill A Z, and E are all located togetherlfin the bot-` tom of the mill. f

Supported upon the slide, and 'at a point where the material in the mill first meets it, is the removable shoe H. (Shown clearly in Figs. 4 and 5.) This shoe or lhood slopes downward toward the end of the plow-bar, and its oflce is to compact the material'to form a grindingsurface against which the rotating material may be abraded. Next in order, the plow-bar G presents itself to the rotating material, and next, again, is the feed opening Z, and next the exhaust-opening E. The openings Zand E are partially protected by projections on the framework."V The plow-bar Gr is curved so as to feed downward at right angles to the plane of rotation ot' theI revolving materialfthat is, its center corresponds with the center of rotation of the revolving material.

The apparatuswith which this mill may be` The exhaust-pipe E connects with the pipe E',

provided with a telescopicjoint allowing ofthe withdrawing ot' the supporting-frame. This pipe E delivers into the selecting-chamber K, which is provided with a delivery-tube, M,'and

automatic valve b. l

The funnel N, provided with a delivery-tube, is located in the upper part of this chamber, and delivers at the valve c, as shown. This chamber K communicates with blower `l? by the pipe R', and the blower P connects at its circumference with pipe It, delivering into the second depositing-chamber, L, which is provided with a delivery-pipe, M', which pipe is provided with an automatic valve,u, as shown. The upper end of this depositing-chamber L is provided with a cloth bag, O, which may be kept extended by cord and weight d, as shown.

IOO

This balloon or bag O allows for the escape ofa certain amount of air in case of a pressure in the chamber L greater than the pressure of the atmosphere,'but sifis out any material suspended in the. air.

l communicates with the delivery-passage D, by

' the shaft B and suitable power.

which the air re-enters the chamber.

It will thus be observed that a continuous and substantially closed circuit is provided for the air which is withdrawn from the mill, and which passes through theselectingapparatuses here shown and again back into the mill.

The operation of my apparatus can now be readily understood. Thechamber A is caused to revolve at a high velocity in the direction shown by the arrow in Fig. 4 by means ot' The material to be reduced is fed to the mill through the feed-opening Z, which may be provided with a suitable hopper and a regulating apparatus for insuring a continuous feed, if desired. Asl soon as the material falls into the mill it immediately rotates with the same velocity as the revolving shell, and it is firmly held against the periphery of this revolving shell by centrifugal force, and it is additionally forced to rotate with lit by the radial ribs orprojections J. In its rotation the material fed to the mill passes underneath the confining and compressing shoe H, and by it is compacted against the plow-bar G intoasolid grinding body or surf'ace. The material to be abraded, which is compacted into a rotatingannulus or ring within the shell, is continually forced against the stationary material held beneath the shoe H and cireumferentially supported by the plow-bar G. So much of said material as passes beneath the plow-bar Gis brought under the iniiuenee of the exhaust passing upward through the opening E, as shown by the arrows, and this exhaust performs a selecting function upon the material passing beneath it, so as to remove only such material as is sufficiently reduced. The size ot' the material to be withdrawn can be determined by the velocity of the exhaust.

The depth to which the plow-bar enters the material may be either regulated by hand and a set-screw, or the bar may be allowed to automaticall y feed to the required depth, its weight carrying it downward, being arrested by the compacted surface of the revolving material against which it would bring up. The feedopenings Z and exhaust openin gs E are likewise protected by removable shoes, although but little wear will be experienced in those parts. When the fan P has been put in operation the abraded material, when sufciently reduced, is drawn through the pipe E and escapes into the selecting or depositing chamber K. In this chamber the velocityof the airis greatly reduced, owing to the greater area of cross-section ot' this chamber than the inlet-passage, and the largest particles which are withdrawn from the mill will fall to the bottom of this 'chamber and be fed out through the deliverypipe M and Valve b. ln the upper part of this chamber the funnel-opening N is placed, and there beinga greater area for the passage of the air above the funnel N than through the annular opening surrounding it a certain additional amount of. reduced material will be there deposited, which material will be of a somewhat finer gradethan that passed through the tube M. The blower I? withdraws the air and its suspended reduced material through the p'ipe R and forces it downward through the pipe R, where most of the remainder ot' the suspended material is deposited, owingto t another reduction in the velocity of the movement of the air, and escapes' through the pipe M andvalve a. Thence the air which has been substantially freed of the lreduced material supported in it is passed onward through the pipe S, flexible pipe T, valve V, pipe D', and return opening D into the mill. By reason of the pervious material of the balloon O, aided, as it may be, by the pervious pipe T, no greater pressure than the pressure of the atmosphere can exist in the pipeRand chamber L, whereby the blo weris relieved from any pressure greater than that of the atmosphere acting against it, and a partial vacuum may be maintained in the mill A and exhaust-tubes E E', so as to prevent the possible escape of any air and dust into the chamber wherein the mill is contained.

By means of the valve V the amount of air to the mill, and consequently the velocity ofthe exhaust, can be-aecurately determined.

By means of the sliding frame Y, telescopic joint in pipe E', andexible tube T,`tl1e feedopenings and plow may be readily withdrawnfromthe mill. Of course other means might kbe devised for accomplishing this same result;

but I have found those shown to be simple and efficient. When desired, the mill, feed-openings, and bar may be made ot' other material than iron-as, for instance, some vitreous material-so as to prevent the discoloration due to the slight amount of iron which may be worn off. By making the inner ribs, J, ot sufficient width tocompress the air in the mill at its peripherythe fan P may be dispensed with, when the material is to be reduced toa very fine degree, because then themill would itself act as a fan forcing the air outward through the airdelivery E. It is plain, likewise, that different forms of selectin g-chambers might be employed without departing from the spirit of my invention. I have shown two selecting-chambers and three delivery-apertures for the material; but it is obvious that one chamber and one aperture might be employed, it' preferred.

What I claim as my invention, and desire to secure by Letters Patent, is

1. The combination, in an attrition-mill, of a transverse plow or bar extending to the out- IOO IOS

side of the mill, a support for said plow ontside of said mill, and appliances whereby theJ plow may bemoved upon said support to the interior otl the mill to compensate for wear at the end of the plow-bar, for the purpose specied. l

2. JThe combination ot' a rotating shell operi at one side, and guides, and a curved plow-bar; secured in said guides, in which it may be `moved in a curved line to carry its end to and from the-inner face of the shell, substantially as set forth. I

3. The combination, in an attrition-mill, of a rotating shell, a slide, a plow-hama feed-tube for delivering the material within the mill, and a. frame adapted to permit the slide to be readily Withdrawn from the mill and replaced therein, substantially as set forth. i i

4. An attrition-mill provided with three independent passages delivering into` the mill from the outside of the chamber, one for the exhaust of' the air from the mill, one for the return of the air so exhausted to the mill, and the other for feeding the material to be reduced to the mill, substantially as set forth.

.5. The combination, in an attrition-mill, of a. shoe constructed todreot the body of material beneath it, and adapted to compress the said material a gai ist the periphery of the mill, and a p1owbar arranged radially across the shell at the rear of and close to the shoe,'and adapted to act against said material, substantially as set forth.

HENRY A. Duo, JR.

Witnesses:

GEO. H. EVANS, WM. A, PoLLooK. 

